PARENT SESSION
Poster Session #18: Remote Sensing and GIS.
Tuesday, August 7, 2001. Presentation from 3:30 PM to 5:00 PM. Exhibition Hall
85
Development of a watershed-based mercury pollution characterization system.
Dai, Ting1, Wool, Timothy2, Ambrose, Robert3, 1 2 3
ABSTRACT- To investigate total mercury loadings to streams in a watershed, we have developed a watershed-based source quantification model — Watershed Mercury Characterization System. The system uses the grid-based GIS modeling technology to calculate total soil mercury concentrations and mercury loadings from direct atmospheric deposition, surface runoff, soil erosion and point sources. The input for the system includes land use, soil type, digital elevation, stream distribution, climate and atmospheric monitoring data. In addition, mercury reduction rate constant in the upper soil layer must be specified. The equations for mercury fate in soils were modified from a pollutant fate and transport model (IEM-2M) developed by U. S. Environmental Protection Agency. Using Watershed Mercury Characterization System, we calculated mercury loads in 20 sub-watersheds in the Savannah River watershed of Georgia and South Carolina. Sensitivity analyses indicate that mercury loading rates from this watershed are affected significantly by the atmospheric deposition flux, the proportion of impervious area, the proportion of direct water surface area, and the soil mercury reduction rate constant. Watershed Mercury Characterization System is distributed as a software extension for ArcView GIS.
KEY WORDS: mercury pollution, GIS, grid modeling, watershed